DESCRIPTION: Severe hypoglycemia (stupor/unconciousness) among individuals with insulin dependent diabetes can result in serious motor vehicle accidents, seizures, and death. Patients may develop considerable anxiety about such episodes which can interfere with efforts to achieve and maintain intensive metabolic control. The investigators have previously developed methods to improve patients' blood glucose awareness. This proposal represents a transition from patients who are unaware of their blood glucose levels to patients with a recent history of severe hypoglycemia. The investigators propose to follow-up unaware patients previously treated by their research team to evaluate whether improved glycemia awareness is maintained 3 years post- treatment. They also propose a series of laboratory and field studies in which patients with recent severe hypolycemia will be compared to patients without such a history. Finally, a revised version of their prior treatment protocol will be developed and tested in a multi-site trial with patients who have a recent history of severe hypoglycemia.